ATLANTA (CBS Atlanta) – While the overall number of people diagnosed with HIV has declined over the last decade in the U.S., the number has risen among young gay men, reports Live Science.

Researchers from the Centers for Disease Control and Prevention looked at data on nearly half-a-million HIV cases diagnosed in the United States in patients 13-years or older between 2002 and 2011.

The annual rate of HIV diagnoses declined by a third: from 24 per 100,000 people in the general American population in 2002 to 16 diagnoses per 100,000 in 2011. The diagnosis rate for women declined by nearly half over the same period.

And the actual number of new HIV cases declined as well, from over 56,000 in 2002 to just over 43,000 in 2011.

But the news for gay men from ages 13 to 24, the news was quite different. The number of HIV diagnoses each year increased 132 percent: from nearly 3,000 in 2002 to nearly 7,000 in 2011.

The number of yearly cases also rose 5 percent among gay men from ages 45 to 54 and 18 percent for gay men ages 55 and over.

“Disparities in rates of HIV among young men who have sex with men present prevention challenges and warrant expanded efforts,” the researchers wrote.

While noting that improved testing methods may lead to an increase in HIV diagnoses, the researchers worried young people are not getting regular tests for the virus that causes AIDS.